(CNN) -- The facility bombed by Israeli warplanes in September was a vacant military building, and any claim that it was a nuclear facility is "ridiculous," Syria's ambassador to the United States said Friday.

Imad Moustapha spoke a day after the White House called the site a covert nuclear reactor that probably was "not intended for peaceful purposes."

Photos the United States provided to him Thursday don't prove anything, Moustapha said.

He argued that they weren't taken in Syria and that there was no proof they came from Syria.

"They were showing me photos from inside a building somewhere in the world," Moustapha said.

He noted that the photos showed just one building -- which didn't have enough power or other complex facilities nearby, such as reprocessing plant for extracting plutonium from spent nuclear fuel -- in order to operate a nuclear program.

A senior congressional aide said Friday that there was a "general consensus" that the presentation was "legitimate." The aide is not authorized to talk on the record because of the sensitivity of the subject matter and spoke only in broad terms.

The administration presented a "compelling case" that the facility was a nuclear reactor and that the North Koreans provided assistance, the aide said. Although the evidence was "less concrete" that the facility was part of a nuclear weapons program, "it is still the conclusion you would draw from the evidence available," the aide continued.

The aide said intelligence analysts considered how the reactor was configured, that there were no power wires going into it or other elements that would be found if it were for energy purposes, that it was not configured for research and that it was in the desert, hidden by berms.

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The evidence was "not as hard, but it doesn't change the conclusion," the aide said.

Another congressional official not authorized to speak for attribution because of the sensitivity of the matter said the evidence was "very convincing" that this was a nuclear facility intended for a weapons program and that the Syrians attempted to "cover up" after it was destroyed in the Israeli raid.

The facility was far from Damascus or any other major city, the official said, and appeared to be based on North Korea's Yongyon weapons plant design.

The evidence was "not ironclad, but intelligence never is," the official said, adding that it was "pretty overpowering."

The reactor was weeks or months away from being functional when Israel bombed it last year, a senior U.S. official said at the reporters' briefing.

In 2005, investigators learned that Syria and North Korea were working together on a project in a remote part of eastern Syria's Dayr az Zawr region, the official said.

Syria would not be "stupid enough" to build a nuclear facility in the middle of a desert without barbed wire or checkpoints, Moustapha added.

"Syria doesn't have a plan or a project to acquire nuclear technology, even for peaceful purposes," he said.

Moustapha described Syria as "puzzled" about why the United States was making the case but said he suspects that the Bush administration is using the presentation to create a crisis in the Middle East and pre-empt calls in Congress for diplomatic engagement with Syria.

He said it was part of the "silly" hardline attitude toward Syria.

The United States has a history of trying to prove that countries have stockpiles of weapons of mass destruction, he said, comparing the new claims to former Secretary of State Colin Powell's presentation to the United Nations about alleged Iraqi weapons of mass destruction.

"Don't be gullible and fall for this," he said.

The Syrian government will "deconstruct" the U.S. story and prove its falsehood within the not-too-distant future, Moustapha said.

Earlier Friday, the head of the U.N. nuclear watchdog agency criticized the United States for not sharing intelligence sooner about the facility.

Mohamed ElBaradei, director general of the International Atomic Energy Agency, said the United States informed him Thursday that it thinks the site was a nuclear reactor.

"The director general deplores the fact that this information was not provided to the agency in a timely manner, in accordance with the agency's responsibilities under the nuclear Non-Proliferation Treaty, to enable it to verify its veracity and establish the facts," ElBaradei wrote, noting that the IAEA was responsible for verifying allegations of a country's pursuit of nuclear weapons.

"The director general views the unilateral use of force by Israel as undermining the due process of verification that is at the heart of the non-proliferation regime."

A working reactor would make Syria the first Arab nation with nuclear capability and potentially would put nuclear weapons in the hands of a regime that the United States accuses of committing human rights abuses and supporting international terror groups.E-mail to a friend